Storyboards, Processes, and Questions...

Now, to clarify, this isn't about constructing the actual storyboard as I already know how to do that. Rather, I'm more curious as to what steps are typically made before a storyboard is officially started. Obviously some form of script is needed in order to start creating panels, but is it common for a script to undergo many rewrites during the actually story board process? Or should the script already be done at this point?

The only reason I ask is because I've been tasked to work on a storyboard (33 panels) for a video our company plans on creating, but the script isn't even finalized yet, and this storyboard has to be delivered within a week and half to the guy narrating our video. =/ Not to mention, next week I have a scheduled trip to the location we plan on shooting at, in order to set up layouts (which will be included in the storyboard). So that causes me to redo X amount of panels that I've already done. >.> While 33 panels isn't much, and revisions aren't anything new to me, I'm still pretty pissed that all of this is cutting it so close to the deadline. And the fact the script isn't finished, the fact the video producer is setting up all the layouts anyway which is rendering my work useless, and pretty much my boss waiting till the last minute to get info to me and generally being unavailable.

I was just more or less curious if this process is in any form the norm for this type of work... or if it's not.